The goal of this project is to provide a molecular picture (theory) of peptide conformations and properties in solution which is consistent with known thermodynamic and structural data. We will make detailed calculations with our new methods in an attempt to make the most direct possible comparisons with recent and planned structural and biological/biochemical experiments. We will consider the relation of thermodynamics and allowed conformations of peptides to their solution environment and salt concentration. Using theoretical methods we will quantify the balance between general solution effects (such as screening and solvation) and specific effects due to molecular association in solutions of peptides in determining the thermodynamics in solution. This will be applied to covalently constrained peptides and peptido mimetics of biochemical and medicinal importance. A goal of this work continues to be the development of new theoretical techniques to solve solvation/conformation related design problems of peptides. Test cases and applications have been chosen to maximize overlap with existing data or collaborations that will yield data of specific relevance to our goal.